
    <nz-collapse>
      <nz-collapse-panel *ngFor="let panel of panels" [nzHeader]="panel.name" [nzActive]="panel.active">
        <p>{{panel.name}}</p>
        <div *ngIf="panel.childPanel&&panel.childPanel.length>0">
          <nz-collapse>
            <nz-collapse-panel *ngFor="let childPanel of panel.childPanel" [nzHeader]="childPanel.name"
              [nzActive]="childPanel.active">
              <p>A dog is a type of domesticated animal. Known for its loyalty and faithfulness, it can be found as a welcome guest in many households across the world.</p>
            </nz-collapse-panel>
          </nz-collapse>
        </div>
      </nz-collapse-panel>
    </nz-collapse>
  